Note: Descriptions are shown in the official language in which they were submitted.
Case EP-7UU0
- 1 21~62~
LUBRICANT COMPOSITIONS OF
ENHANCED PERFORMANCE CAPABILITIES
TECHNICAL FIELD
This invention relates to novel and eminently useful dispersant compositions for use
5 in lubricating oils, especially in the formulation of engine oils, and most especially heavy
duty crankcase lubricating oil compositions and additive concentrates therefor.
BACKGROUND
In the formulation of lubricant additive concentrates (also known as I)I-packages)
and finished lubricating oils such as crankcase lubricating oils, one is continuously
10 confronted by the truism that things never stand still. In order to be sl~ccecsful in the field,
it is necessary to provide compositions which satisfy ever-increasingly difficult
perforrnance demands imposed upon them by purchasers, consumers original equipment
manufacturers, and industry groups. One of the key components in such compositions is
the dispersant component, and in order to have any chance of achieving the present-day
15 performance standards the dispersant must not only be highly effective in its own right,
but must be capable of m~int~ining its high performance level when in combination with
various other components utilized in the search for compositions that can achieve the these
standards. And in this search, the performance interactions arnong components of a
proposed DI-package can only be ascertained by e~cperiment. Then, and only then, can
20 valid predictions be made concerning performance capabilities of a given class of
formulations.
GLOSSARY OF TERMS
As used herein, GPC means gel perrneation chromatography using calibrated
columns in accordance with known procedures, the succination ratio is the ratio of succinic
25 groups to alkenyl groups chemically bound together in the chemical structure of the disper-
sant, TBN means total base number in terms of mg KOH per gram of detergent
(,ase ~ uuo
2158627
composition using the ASTM D2896 procedure, and TSA means total sulfated ash in terms
of weight percent using the ASTM D874 procedure.
THE INVENTION
In accordance with this invention there is provided a novel dispersant composition
which has been found to possess the necessary level of high dispersancy performance.
Moreover, when suitably formulated pursuant to this invention, lubricants can be formed
that exhibit excellent performance in a wide variety of rigorous qualification tests.
In accordance with one embodiment of this invention there is provided a dispersant
composition which comprises
10 a) a first succinic derivative dispersant produced by reacting (i) a substituted succinic
acylating agent in which the substituent is an aliphatic group derived from
polyalkene having a GPC number average molecular weight in the range of about
700 to about 2500, preferably about 800 to about 1400 with (ii) alkylene polyamine
having an average of about 3 to about 6 nitrogen atoms per molecule, wherein (i)has a succination ratio below 1.3 and wherein the mole ratio of (i) to (ii) in said
first succinic derivative dispersant is below about 1.85, preferably in the range of
about 1.75 to about 1.85; and
b) a second succinic derivative dispersant produced by reacting (iii) a substituted
succinic acylating agent in which the substituent is an aliphatic group derived from
polyalkene having a GPC number average molecular weight in the range of about
1100 to about 2800 with (iv) hydroxypropylated alkylene diamine having an
average of 2 to about 12 carbon atoms per molecule and an average of about 2.5
to about 3.5 hydroxypropyl groups per molecule, wherein (iii) has a succination
ratio below about 1.~ and wherein the mole ratio of ~iii) to (iv) in said secondsuccinic derivative dispersant is in the range of 1.0 to about 1.5;
the weight ratio of a) to b) being such that on an active ingredient basis there are from
about 0.25 to about 10 parts by weight of a) per part by weight of b), and preferably from
about 0.5 to about 5 parts by weight of a) per part by weight of b). As an additive
composition, components a) and b) are normally in admixture with a minor amount of a
diluent oil such as a light mineral oil. When components a) and b) are formulated into
(~ase k;l:'-'/UUU
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lubricant compositions, the overall composition typically comprises a major amount of at
least one oil of lubricating viscosity.
Components a) and b) proportioned as above work effectively with alkali andJor
alkaline earth metal-cont~ining detergents (e.g., sulfonates, phenates, sulfurized phenates,
S and carboxylates) to effectively control accumulation of deposits, sludge and varnish on
engine parts. Enhanced stability and wear inhibition are achieved by combining an oil-
soluble dithiophosphate material with components a) and b) proportioned as above,
particularly when alkali and/or alkaline earth metal-cont~ining detergents are also included
in the composition. Still greater stability results by including in these compositions one
or more oil-soluble antioxidants such as are described hereinafter.
The amount of components a) and b), proportioned as specified above, and on an
active ingredient basis (i.e., excluding the weight of any solvent or diluent associated with
either or both such components) in the finished lubricants of this invention typically will
be in the range of about 1 to about 10 wt%, and preferably in the range of about 2 to
about 5 wt%, of the total weight of the finished lubricant composition. Most preferably,
the amount will be in the range of about 3 to about 4 wt% of the total weight of the
finished lubricant composition.
Preferably component b) is borated by reaction with a suitable boron-cont;~iningreagent. On the other hand, component a) is preferably utilized in non-borated form.
A preferred embodiment of this invention from the cost-effectiveness standpoint in
the control of deposit, sludge and varnish accurnulation on engine parts is a lubricant
additive composition or finished lubricating oil composition which comprises components
a) and b) above and a detergent complement composed of c) at least one calcium phenate
or calcium sulfurized phenate composition having a TBN in the range of about 160 to
about 260, and d) at least one calcium sulfonate having a TBN of up to about 420. When
the calcium sulfonate used has a TBN of up to about 50 (e.g., in the range of about 20 to
about 50), the total TSA content of the finished lubricant is preferably no higher than
about 1.8 wt%, e.g., in the range of about 0.2 to about 1.8 wt%, and more preferably in
the range of about 0.4 to about 1.4 wt%. Thus when using a calcium sulfonate having a
TBN of up to about 50 in preparing an additive concentrate of this invention, the
concentrate is preferably formulated such that at the recomrnended dosage level of the
(3ase ~-/()W
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concentrate in the finished oil, the TSA content of the finished lubricant will be no higher
than about 1.8 wt%, and more preferably will be in the range of about 0.4 to about 1.4
wt%. On the other hand, when the calcium sulfonate used has a TBN greater than about
50 (e.g., in the range of about ~0 to about 420), the TSA content of the finished lubricant
5 is preferably up to about 2.5 wt%, e.g., in the range of about 0.7 to about 2.5 wt%, and
more preferably in the range of about 0.8 to about 2.2 wt%. Thus when using a calciurn
sulfonate having a TBN of greater than about 50 in preparing an additive concentrate of
this invention, the concentrate is preferably formulated such that at the recommended
dosage level of the concentrate in the finished oil, the TSA content of the finished
10 lubricant is preferably no higher than about 2.5 wt%, and more preferably will be in the
range of about 0.8 to about 2.2 wt%.
Still another preferred embodiment of this invention is a lubricant or additive
concentrate cont~ining components a) and b) above and e) at least one oil-soluble
dithiophosphate material in an arnount such that the finished lubricant contains in the range
15 of about 0.02 to about 0.18 wt% of phosphorus, and preferably in the range of about 0.06
to about 0.15 wt % phosphorus, as the dithiophosphate material. These combined additives
work together to provide highly effective control of wear, as well as control of sludge and
varnish deposition. The inclusion in these compositions of components c) and d) in the
proportions described above constitutes a particularly p.er~lled embodiment of this
20 invention.
Additional preferred embodiments of this invention are lubricants and additive
concentrates as described above which contain f) at least one oil-soluble antioxidant,
preferably at least one secondary aromatic arnine antioxidant. Most preferably the lubri-
cant or additive concentrate additionally contains one or more additional antioxidants such
25 as (i) at least one oil-soluble sulfurized olefin having about 10 to about 30 carbon atoms
in the molecule (preferably an average of about 16 to about 24 carbon atoms per
molecule), and a sulfur content of about 15 to 25 wt%; and/or (ii) at least one oil-soluble
sulfurized phenol having about 30 to about 100 carbon atoms in the molecule (preferably
an average of about 50 to about 70 carbon atoms per molecule), and a sulfur content of
30 about 5 to 15 wt%; and/or (iii) an oil-soluble phenolic antioxidant, preferably an oil-solu-
ble hindered phenolic antioxidant; and/or (iv) an oil-soluble copper-cont~ining antioxidant.
Case EP-7000
2iS8627
The foregoing materials whether used singly or in combinations are used in amounts suffi-
cient to inhibit oxidative degradation, i.e., they are used in antioxidant quantities. Thus
in most cases the amount of antioxidant(s) used in formulating the additive concentrates
of this invention are such that the finished lubricants of this invention will typically contain
S in the range of about 0.2 to about 0.8 wt% of the antioxidant component(s). The copper
antioxidants are typically employed in the finished lubricants in amounts corresponding to
not more than about 500 ppm of copper.
Further preferred embodiments of this invention are lubricants and additive
concentrates as described above which contain g) at least one oil-soluble demulsifying
agent and/or h) at least one oil-soluble corrosion inhibitor, especially a rust inhibitor. The
demulsifiers are used in amounts such that the finished lubricant contains a demulsifying
amount thereof, typically in the range of about 0.005 to about 0.2 wt% and preferably in
the range of about 0.005 to about 0.1 wt%. The amounts of corrosion or rust inhibitors
used are such that the finished lubricant contains a corrosion-inhibiting or rust-inhibiting
amount thereof, typically in the range of about 0.05 to about 0.5 wt% and preferably in
the range of about 0.05 to about 0.3 wt%.
The additive concentrates of this invention will normally contain a minor amount(and preferably no more than about 40% by weight) of one or more inert diluents such as
light mineral oil. These diluents, or a portion thereof, may be one or more diluents which
were associated with one or more components used in formulating the additive concentrate
(sometimes referred to as a "DI-package"). The balance of the additive concentrate is
composed of the additive components being utilized in the concentrate.
These and still other embodiments of this invention will become still further
apparent from the ensuing description and appended claims.
A feature of this invention is that the dispersant compositions of this invention are
more effective in providing high telllpeldlllre piston cleanliness performance than the
closest known prior art dispersant composition, a dispersant composition which was used
in heavy duty diesel lubricants. That composition was composed of component b) as
described above and a succinimide dispersant of the same type as the above component
a) except that the mole ratio of (i) to (ii) thereof was 2:1 instead of below about 1.85 as
re4uired pursuant to this invention. When used as the dispersant on three occasions in an
Case EP-70~)0
2158627
SAE 15W-40 heavy duty engine oil forrnulation that satisfied the requirements of API
classification CE, the prior art dispersant gave three failing results in the Caterpillar lK
engine test procedure. In sharp contrast, four different SAE lOW-40 heavy duty engine
oils of this invention in which the dispersant was a dispersant composition of this invention
all passed the Caterpillar IK engine test. The test data are presented hereinafter.
Another feature of this invention is that the compositions of this invention enable
formulation of finished heavy duty engine oils which can pass a wide variety of rigorous
qualification tests required for commercial acceptance. Illustrative data are presented
hereinafter.
Coml~onent a)
As noted above the novel dispersant systems of this invention comprise two
carefully defined components, both of which are succinic derivative dispersants. The first
such dispersant component is produced by reacting (i) a substituted succinic acylating
agent in which the substituent is an aliphatic group derived from polyalkene having a GPC
number average molecular weight in the range of about 700 to about 2500, preferably
about 800 to about 1400 with (ii) alkylene polyamine having an average of about 3 to
about 6 nitrogen atoms per molecule, wherein (i) has a succination ratio below 1.3 and
wherein the mole ratio of (i) to (ii) in said first succinic derivative dispersant is below
about 1.85, preferably in the range of about 1.75 to about 1.85.
The substituted succinic acylating agent used in forming component a) is an alkenyl
succinic anhydride, alkenyl succinic acid, alkenyl succinic partial acid-partial lower ester,
alkenyl succinic acid halide, or alkenyl succinic lower alkyl ester. Of these, the use of an
alkenyl succinic anhydride is preferred as these acylating agents are readily prepared by
heating a mixture of a polyolefin and-maleic anhydride to about 180-220C. The reaction
can be conducted in the presence of a small amount of a catalyst such as alllminllm
chloride, and the polyolefin can be reacted with a small amount of chlorine to enhance
reaction rate. In lieu of, or in addition to, maleic anhydride, the polyolefin or chlorinated
polyolefin can be reacted with other similar materials such as maleic acid, fumaric acid,
itaconic acid, or the like, including mixtures of two or more such substances. The poly-
olefin is preferably a polymer or copolymer of a lower monoolefin such as ethylene, pro-
-6-
Case EP-7000
2158627
pylene, l-butene, isobutene and the like. The more preferred source of alkenyl group is
from polyisobutene having a number average molecular weight of 700 to about 2500, and
preferably in the range of about 800 to about 1400. In a still more preferred embodiment
the alkenyl group is a polyisobutenyl group having a number average molecular weight in
5 the range of about 1200 to about 1400. The number average molecular weights are
typically deterrnined by use of gel perTneation chromatography (GPC) using columns
calibrated by use of standard polymers of controlled molecular weight. The well-known
manufacturers and suppliers of such polymers normally identify the molecular weights of
their polymers in this manner, and the molecular weight values given by such reliable
lO suppliers for their polyolefin products such as polyisobutene can safely be relied upon
when selecting the respective polymers for use in preparing the acylating agents used for
making component a) and component b).
The isobutene used in making the polyisobutene is usually (but not necessarily) a
mixture of isobutene and other C4 isomers such as l-butene. Thus, strictly speaking, the
15 acylating agent formed from maleic anhydride and "polyisobutene" made from such
mixtures of isobutene and other C4 isomers such as l-butene, can be termed a "polybutenyl
succinic anhydride" and a succinimide made therewith can be termed a "polybutenyl
succinimide". However, it is common to refer to such substances as "polyisobutenyl
succinic anhydride" and "polyisobutenyl succinimide", respectively. As used herein
20 "polyisobutenyl" is used to denote the alkenyl moiety whether made from a highly pure
isobutene or a more impure mixture of isobutene and other C4 isomers such as l-butene.
The alkylene polyamines used in forming component a) contain a substantial
proportion (e.g., at least about 50 wt%, and preferably at least about 70 wt%) of alkylene
polyamine species having at least one primary amino group capable of forming an imide
25 group on reaction with a hydrocarbon-substituted succinic acid or acid derivative thereof
such an anhydride, lower alkyl ester, acid halide, or acid-ester. Representative examples
of such materials include the ethylene polyarnines, the propylene polyamines and the
butylene polyamines, and these may be linear and/or branched and may include cyclic
species. Highly pure alkylene polyamines can be used if desired, although it is generally
30 preferred for economic reasons to use technical grade materials which containcombinations of linear, branched and cyclic species. Small proportions of hydroxy-substi-
Case EP-7000
2158627
-
tuted alkylene polyamines species may also be present in suitable commercial alkylene
polyarnine products.
Individual linear ethylene polyamines and linear ethylene polyamine mixtures canbe depicted by the formula H2N(CH2CH2NH)nH. In the individual compounds when used
5 as such, n is from about 3 to about 6. When mixtures are used, n is an integer from 1 to
about 10 for individual species in the mixture, with the overall mixture having an average
value for n in the range of about 3 to about 6. These linear mixtures may include:
ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamille,
pentaethylene hexamine, hexaethylene heptarnine, heptaethylene octamine, octaethylene
10 nonamine, and the like. These ethylene polyamines have a primary amine group at each
end and thus can forrn mono-alkenylsuccinimides and bis-alkenylsuccinimides.
Commercially available ethylene polyamine mixtures usually contain minor amountsof branched species such as tris(2-aminoethyl)amine and N,N-di(2-
aminoethyl)diethylenetriamine, and cyclic species such as N-arninoethyl piperazine,
15 N,N'-bis(aminoethyl)piperazine, N,N'-bis(pipc;~ yl)ethane, and like compounds.
Commercially-available product mixtures known in the art as triethylene tetramine,
tetraethylene pentamine and pentaethylene hexamine are examples of suitable alkylene
polyamines. The preferred commercial mixtures have approximate overall compositions
falling in the range corresponding to diethylene triamine to pentaethylene hex~mine, mix-
20 tures generally corresponding in overall makeup to tetraethylene pentarnine being mostpreferred. Methods for the production of polyalkylene polyamines are known and reported
in the literature. See for example U.S. Pat. No. 4,827,037 and references cited therein.
As used herein the term "succinimide" is meant to encompass the completed
reaction product from reaction between the amine reactant(s) and the hydrocarbon-
25 substituted carbo~ylic acid or anhydride (or like acid derivative) reactant(s), and isintended to encompass compounds wherein the product may have amide, amidine, and/or
salt linkages in addition to the imide linkage of the type that results from the reaction of
a primary amino group and an anhydride moiety.
Details on methods for preparing succinic acylating agents and succinimide
30 dispersants are given, for exarnple, in U.S. Pat. Nos. 3,172,892; 3,202,678; 3,216,936;
3,219,666; 3,254,025; 3,272,746; 4,234,435; 5,071,919; 5,137,978; and 5,137,980. Such
Case EP-7000
21~8627
general methods can be employed, provided that (l) the polyolefIn used in forming the
substituted succinic acylating agent has the requisite number average molecular weight as
described above, ~2) the succination ratio of the substituted succinic acylating agent is
below about 1.3, and (3) the succinic acylating agent and alkylene polyamine are reacted
5 in proportions such that a succinimide product is produced in which the mole ratio of
succinic acylating agent to alkylene polyarnine is below about 1.85.
Residual unsaturation in the alkenyl group of the alkenyl succinimide may be used
as a reaction site, if desired. For example the alkenyl substituent may be hydrogenated to
form an alkyl substituent. Similarly the olefinic bond(s) in the alkenyl substituent may be
10 sulfurized, halogenated, hydrohalogenated or the like. Ordinarily, there is little to be
gained by use of such techniques, and thus the use of alkenyl succinimides is preferred.
HiTEC(~) 646 additive (Ethyl Petroleum Additives, Inc.) is a highly pref~ d
commercially available product for use as component a).
Component b)
The second succinate derivative dispersant utilized pursuant to this invention is
produced by reacting a substituted succinic acylating agent in which the substituent is an
aliphatic group derived from polyalkene having a GPC number average molecular weight
in the range of about l 100 to about 2800 with hydroxypropylated alkylene diamine having
an average of 2 to about 12 carbon atoms per molecule and an average of about 2.5 to -
20 about 3.5 hydroxypropyl groups per molecule. The substituted succinic acylating agent-
used for preparing component b) has a succination ratio below about 1.3, and the mole
ratio of the acylating agent to the hydroxypropylated alkylene diamine in component b)
is in the range of 1.0 to about 1.5.
The substituted succinic acylating agent used in producing component b) is made
25 in similar manner to the succinic acylating agent used in forming component a) with the
exception that the GPC number average molecular weight for the component b) acylating
agent is in the range of about 1100 to about 2800.
Hydroxypropylated alkylene diamines used in forming component b) have an
average of 2 to about 12 carbon atoms per molecule and an average of about 2.5 to about
30 3.5 hydroxypropyl groups per molecule. These products are readily made by reacting
Case EP-7000
21~627
propylene oxide with an alkylene diamine having from 2 to about 12 carbon atoms per
molecule. The alkylene diamines can be individual compounds or mixtures of the
individual compounds. Thus the alkylene diamines can be represented by the formula
H2N-R-~'H2 where R is an alkylene group of from 2 to about 12 carbon atoms. The
S alkylene group can be straight or branched chain in structure. A particularly pl~r~;~led
alkylene diamine is hexamethylene diamine.
The propoxylation reaction is typically conducted at a temperature in the range of
about 50 to about 200C. The propylene oxide and alkylene diamine are proportioned such
that the resultant hydroxypropylated alkylene diarnine product has an average of about 2.5
10 to about 3.5 hydroxypropyl groups per molecule.
Reaction between the appropriate substituted succinic acylating agent and the
hydroxypropylated alkylene diarnine is conducted by proportioning these re~et~nt.~ such
that the mole ratio of the acylating agent to the hydroxypropylated alkylene diamine in the
resultant product is in the range of 1.0 to about 1.5. This reaction is preferably carried out
15 in a suitable reaction diluent such as a light mineral oil. A suitable temperature in the
range of about 100 to about 250C is employed for effecting the reaction between the
substituted succinic acylating agent and the hydroxypropylated alkylene ~i~mine.When it is desired to use cornponent b) in borated form, boration of the productformed by reaction between the substituted succinic acylating agent and the hydroxy-
20 propylated alkylene diamine is usually effected by heating the product with a suitableborating agent such as a boron acid, a boron ester, a boron oxide, a boron halide, an
ammonium salt of a boron acid, a super-borated ashless dispersant (i.e., a dispersant that
has been heated with a large amount of a boron compound such as a boron acid, oxide or
ester and thus is itself suitable as a borating agent), or the like. The boron compound can
25 be reacted in a ratio of from about 0.-1 to about 10 moles of boron compound per mole of
the product formed by reaction of the substituted acylating agent and the
hydroxypropylated alkylene diamine. It is also possible, but less preferred to conduct the
boration concurrently with the reaction between the substituted succinic acylating agent and
the hydroxypropylated alkylene diamine. Another possible alternative is to borate the
30 hydroxypropylated alkylene diamine prior to conducting the acylation reaction.
When and however borated, component b) will typically contain from about 0.05
-10-
Case EP-7000
2158627
to about 7.5 weight percent of boron, preferably from about 0.1 to about 6.5 weight
percent of boron, and most preferably from about 0.2 to about I weight percent of boron,
each based on the weight of component b), and excluding the weight of any solvent or
diluent that may be, and usually is, associated therewith.
Details concerning the synthesis of products suitable for use as component b) can
be found within the disclosure of U.S. Pat. No. 4,873,009. An excellent commercially
available product for use as component b) is HiTEC(~) 7714 additive (Ethyl Petroleum
Additives, Inc.).
Metal-containing detergents
The metal-cont~ining detergents which preferably are employed in conjunction with
components a) and b) of the compositions of this invention oil-soluble or oil-dispersible
metal salts of one or more suitable organic acids. Such detergents are exemplified by
oil-soluble salts of alkali or alkaline earth metals with one or more of the follo~,ving acidic
substances (or mixtures thereof): (l) sulfonic acids, (2) carboxylic acids, and (3)
alkylphenols or sulfurized alkylphenols. Other metal-containing detergents are known and
can be used if desired. For example, metal salts of organic phosphorus acids that have at
least one direct carbon-to-phosphorus linkage can be used. Also useful are metal calix-
arates such as are described in U.S. Pat. Nos 5,114,601 and 5,205,946.
The most commonly used metal detergent salts are those in which the metal is an
alkali metal or an alkaline earth metal, especially sodium, potassium, lithium, calcium,
magnesiurn, and barium. The salts preferably comprise basic salts having a TBN of at
least 50, preferably above 100, and most preferably above 200. However neutral or low-
base metal-containing detergents can also be included in the compositions of this invention.
The neutral or low-base d~tergellLs of this type are those which contain an essentially
stoichiometric e~uivalent quantity of metal in relation to the amount of acidic moieties
present in the detergent. Thus in general, the neutral detergents will have a TBN of up to
about 50. Combinations of neutral or low-base detergents and overbased detergents can
also be employed.
The term "basic salt" is sometimes used to designate metal salts wherein the metal
is present in stoichiometrically larger amounts than the organic acid radical. Such
-1 1-
~ase ~ w)()
_ 215~627
materials are usually referred to as "overbased" detergents, or by similar terms such as
superbased or hyperbased detergents. Commonly employed methods for preparing theoverbased salts involve heating a mineral oil solution of an acid with a stoichiometric
excess of a metal neutralizing agent such as the metal oxide, hydroxide, carbonate,
5 bicarbonate, or sulfide at a moderate reaction temperature in the range of about 40 to about
100C, treating the mixture with an acidic gaseous substance, and filtering the resulting
mass. The use of a "promoter" to aid the incorporation of a large excess of metal in the
product likewise is known. Examples of compounds useful as the promoter include phe-
nolic substances such as phenol, naphthol, alkylphenol, thiophenol, sulfurized alkylphenol,
10 and condensation products of formaldehyde with a phenolic substance; alcohols such as
methanol, 2-propanol, octyl alcohol, ethylene glycol, ethylene glycol monoalkyl ethers,
diethylene glycol monoalkyl ethers, stearyl alcohol, and cyclohexyl alcohol; and amines
such as aniline, phenylenediamine, phenothi~7in~, phenyl-~-naphthylamine, and dodec-
ylamine. A particularly effective method for pre~allllg the basic salts comprises mixing
15 an acid with an excess of a basic alkali or alkaline earth metal neutralizing agent and at
least one alcohol promoter, and carbonating the mixture at an elevated te~ eldture such
as 60-200C.
Examples of suitable metal-cont~ining detergents include, but are not limited to, the
neutral, low-base and overbased phenates and sulfurized phenates (phenol sulfides) of lithi-
20 um, sodium, potassium, calcium, and magnesium wherein each aromatic group has one ormore aliphatic groups to impart hydrocarbon solubility; the neutral, low-base and
overbased sulfonates of lithium, sodium, potassium, calcium, and magnesium wherein each
sulfonic acid moiety is attached to a long chain aliphatic group, or to a cycloaliphatic or
aromatic nucleus which in turn usually contains one or more aliphatic substituents to im-
25 part hydrocarbon solubility; lithium,-sodium, potassium, calcium and magnesium salts of
aliphatic carboxylic acids and aliphatic-substituted cycloaliphatic carboxylic acids; and
many other similar alkali and alkaline earth metal salts of oil-soluble organic acids such
as the salicylates and succinates in which the acid moiety contains at least one aliphatic
substituent (e.g. an alkyl or alkenyl group) of sufficient chain length to render the
30 compound oil soluble. Mixtures of overbased salts of two or more different alkali and/or
alkaline earth metals can be used. Likewise, basic or overbased salts of mixtures of two
(~ase ~
215g~27
_
or more different acids or two or more different types of acids (e.g.~ one or more calcium
phenates with one or more calcium sulfonates) can also be used. While rubidium, cesium
and strontium salts are feasible, their expense renders them less preferred for most uses.
Likewise, while barium salts are effective, the status of barium as a heavy metal under a
5 toxicological cloud renders barium salts less preferred for present-day usage.As is well known, overbased metal detergents are generally regarded as cont~ining
overbasing quantities of inorganic bases, probably in the form of micro dispersions or
colloidal suspensions. Thus the term "oil-soluble" as applied to the metal-cont~ining deter-
gent materials is intended to include metal detergents wherein inorganic bases are present
10 that are not necessarily completely or truly oil-soluble in the strict sense of the term,
inasmuch as such detergents when mixed into base oils behave in much the same way as
if they were fully and totally dissolved in the oil.
Collectively, the various basic or overbased detergents referred to hereinabove, have
sometimes been called, quite simply, basic alkali metal or alkaline earth metal-cont~ining
15 organic acid salts.
Dithiophosphate material
Preferred compositions of this invention contain at least one oil-soluble
dithiophosphate material, i.e., one or more salts of hydrocarbyl dithiophosphates. Such
materials are usually prepared by reacting phosphorus pentasulfide with one or more
20 alcohols or phenolic compounds or diols to produce a hydrocarbyl dithiophosphoric acid
which is then neutralized with one or more bases, such as an amine to form an amine salt
of the dithiophosphoric acid or a metal base to forrn a metal salt of the dithiophosphoric
acid. When a monohydric alcohol or phenol is used in forming the dithiophosphoric acid,
a dihydrocarbyl dithiophosphoric acid is formed. On the other hand, when a suitable diol
25 (e.g., 2,4-pentanediol) is used in this reaction, a cyclic hydrocarbyl dithiophosphoric acid
is produced. See, for example, U.S. Pat. No. 3,089,850. Thus typical oil-soluble metal
hydrocarbyl dithiophosphates used as component a) may be represented by the formula
R ~ \1 1
~P--S M
R 2 o -13- - x
- (~ase kl'-1()~)()
21r~86~7
where R, and R, are, independently, hydrocarbyl groups or taken together are a single
hydrocarbyl group forming a cyclic structure with the phosphorus and two oxygen atoms,
preferably a hydrocarbyl-substituted trimethylene group of sufficient carbon content to ren-
der the compound oil soluble, M is a metal or a nitrogen base such as an amine, and x is
5 an integer corresponding to the valence of M. The preferred compounds are those in
which R, and R~ are separate hydrocarbyl groups (i.e., the salts of dihydrocarbyl dithio-
phosphoric acids). Usually each hydrocarbyl group of the ;dithiophosphate materials will
contain no more than about 50 carbon atoms although even higher molecular weighthydrocarbyl groups can be present in the compound. The hydrocarbyl groups include
lO cyclic and acyclic groups, both saturated and unsaturated, such as alkyl7 cycloalkyl,
alkenyl, cycloalkenyl, aryl, cycloalkylalkyl, aralkyl, and the like. It will be understood that
the hydrocarbyl groups may contain elements other than carbon and hydrogen provided
such other elements do not detract from the predomin~ntly hydrocarbonaceous character
of the hydrocarbyl group. Thus the hydrocarbyl groups may contain ether oxygen atoms,
l 5 thioether sulfur atoms, secondary or tertiary amino nitrogen atoms, and/or inert functional
groups such as esterified carboxylic groups, keto groups, thioketo groups, and the like.
The metals present in the oil-soluble metal dihydrocarbyl dithiophosphates and oil-
soluble metal cyclic hydrocarbyl dithiophosphates include such metals as lithium, sodium,
potassium, copper, m~nesium, calcium, zinc, strontium, cadmium, barium, mercury, alu-
20 minum, tin, lead, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel,
ruthenium, etc., as well as combinations of two or more such metals. Of the foregoing,
the salts containing group II metals, aluminum, lead, tin, molybdenum, m~ng~nese~ cobalt,
and/or nickel, are preferred. The dihydrocarbyl dithiophosphates of zinc and copper are
particularly preferred, with the zinc salts being the most preferred for use in the practice
25 of this invention.
The phosphorodithioic acids from which the metal salts are formed can be prepared
by the reaction of about 4 moles of one or more alcohols (cyclic or acyclic) or one or
more phenols or mixture of one or more alcohols and one or more phenols (or about 2
moles of one or more diols) per mole of phosphorus pentasulfide, and the reaction may be
30 carried out within a temperature range of from about S0 to about 200C. The reaction
generally is completed in about l to lO hours. Hydrogen sulfide is liberated during the
-14-
(~ase ~-7000
2158627
reaction.
Other methods for the preparation of the phosphorodithioic acids are known, and
if suitable, can be used. Note, for example, PCT International Publication No. WO
90/07512, which describes reaction of one or more alcohols and/or one or more phenols
with phosphorus sesquisulfide in the presence of sulfur at an elevated temperature,
preferably in the range of 85-150C with an overall atomic P:S ratio of at least 2.5:1.
The alcohols used in forming the phosphorodithioic acids by either of the above
methods are preferably primary alcohols, or secondary alcohols. Mixtures thereof are also
suitable. The primary alcohols include propanol, butanol, isobutyl alcohol, pentanol, 2-
ethyl- 1 -hexanol, isooctyl alcohol, nonanol, decanol, undecanol, dodecanol, tridecanol,
tetradecanol, octadecanol, eicosanol, and the like. The primary alcohols may contain
various substituent groups such as halogen atoms, nitro groups, etc., which do not interfere
with the desired reaction. Among suitable secondary alcohols are included 2-butanol, 2-
pentanol, 3-pentanol, 2-hexanol, 5-methyl-2-hexanol, and the like. In some cases, it is
preferable to utilize mixtures of various alcohols, such as mixtures of 2-propanol with one
or more higher molecular weight primary alcohols, especially primary alcohols having
from 4 to about 13 carbon atoms in the molecule. Such mixtures preferably contain at
least 10 mole percent of 2-propanol, and usually will contain from about 20 to about 90
mole percent of 2-propanol. In one p,er~ll, d embodiment, the alcohol comprises about
30 to 50 mole percent of 2-propanol, about 30 to 50 mole percent isobutyl alcohol and
about 10 to 30 mole percent of 2-ethyl-1-hexanol.
Other suitable mixtures of alcohols include 2-propanol/butanol; 2-propanol/2-
butanol; 2-propanol/2-ethyl-1-hexanol; butanol/2-ethyl-1-hexanol; isobutyl alcohol/2-ethyl-
l-hexanol; and 2-propanol/tridecanol.
Cycloaliphatic alcohols suitable for use in the production of the phosphorodithioic
acids include cyclopentanol, cyclohexanol, methylcyclohexanol, cyclooctanol, borneol and
the like. Preferably, such alcohols are used in combination with one or more primary
alkanols such as butanol, isobutyl alcohol, or the like.
Illustrative phenols which can be employed in forming the phosphorodithioic acids
include phenol, o-cresol, m-cresol, p-cresol, 4-ethylphenol, 2,4-xylenol, and the like. It is
desirable to employ phenolic compounds in combination with primary alkanols such
(~ase ~ 7U()()
- 2158G27
propanol, butanol, hexanol, or the like.
Other alcohols which can be employed include benzyl alcohol, cyclohexenol, and
their ring-alkylated analogs.
It will be appreciated that when mixtures of two or more alcohols and/or phenols5 are employed in forming the phosphorodithioic acid, the resultant product will normally
comprise a mixture of three or more different dihydrocarbyl phosphorodithioic acids, usu-
ally in the form of a statistical distribution in relation to the number and proportions of
alcohols and/or phenols used.
Illustrative diols which can be used in forming the phosphorodithioic acids include
10 2,4-pentanediol, 2,4-hexanediol, 3,5-heptanediol, 7-methyl-2,4-octanediol, neopentyl glycol,
2-butyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, and the like.
The preparation of the metal salts of the dihydrocarbyl dithiophosphoric acids or
the cyclic hydrocarbyl dithiophosphoric acids is usually effected by reacting the acid
product with a suitable metal compound such as a metal carbonate, metal hydroxide, metal
15 alkoxide, metal oxide, or other appropriate metal salt. Simply mixing and heating such
reactants is normally sufficient to cause the reaction to occur and the resulting product is
usually of sufficient purity for use in the practice of this invention. Typically, the salts are
formed in the presence of a diluent such as an alcohol, water or a light mineral oil.
Neutral salts are prepared by reacting one equivalent of metal oxide or hydroxide with one
20 equivalent of the acid. Basic metal salts are prepared by adding an excess (i.e., more than
one equivalent) of the metal oxide or hydroxide with one equivalent of the dihydrocarbyl
phosphorodithioic acid or cyclic hydrocarbyl phosphorodithioic acid.
Illustrative metal compounds which may be used in such reactions include calciumoxide, calcium hydroxide, silver oxide, silver carbonate, magnesium oxide, magnesium
25 hydroxide, magnesium carbonate, magnesium ethoxide, zinc oxide, zinc hydroxide, stron-
tium oxide, strontium hydroxide, cadmium oxide, cadmium hydroxide, cadmium carbonate,
barium oxide, aluminum oxide, aluminum propoxide, iron carbonate, copper hydroxide,
lead oxide, tin butoxide, cobalt oxide, nickel hydroxide, m~ng;~nese oxide, and the like.
In some cases, incorporation of certain ingredients such as small amounts of metal
30 acetate or acetic acid in conjunction with the metal reactant will facilitate the reaction and
provide an improved product. For example, use of up to about 5% of zinc acetate in
-16-
(~ase ~ 7U()~)
2158G27
combination with the required arnount of zinc oxide tends to facilitate the forrnation of
zinc dihydrocarbyl dithiophosphates.
Examples of useful metal salts of dihydrocarbyl dithiophosphoric acids, and
methods for preparing such salts are found in the prior art such as for exarnple, U.S. Pat.
Nos. 4,263,150; 4,289,635; 4,308,154; 4,322,479; 4,417,990; and 4,466,895.
Generally speaking, the preferred types of metal salts of dihydrocarbyl
dithiophosphoric acids are the oil-soluble metal salts of dialkyl dithiophosphoric acids.
Such compounds generally contain alkyl groups having at least three carbon atoms, and
preferably the alkyl groups contain up to 10 carbon atoms although as noted above, even
higher molecular weight alkyl groups are entirely feasible. A few illustrative zinc dialkyl
dithiophosphates include zinc diisopropyl dithiophosphate, zinc dibutyl dithiophosphate,
zinc diisobutyl dithiophosphate, zinc di-sec-butyl dithiophosphate, the zinc dipentyl
dithiophosphates, the zinc dihexyl dithiophosphates, the zinc diheptyl dithiophosphates, the
zinc dioctyl dithiophosphates, the zinc dinonyl dithiophosphates, the zinc didecyl
dithiophosphates, and the higher homologs thereof. Mixtures of two or more such metal
compounds are often preferred for use such as metal salts of dithiophosphoric acids forrned
from mixtures of isopropyl alcohol and secondary butyl alcohol; isopropyl alcohol, isobutyl
alcohol, and 2-ethylhexyl alcohol; isopropyl alcohol, butyl alcohol, and pentyl alcohol;
isobutyl alcohol and octyl alcohol; and the like.
The preparation of the organic salts of organic dithiophosphoric acids usually
involves reacting an apl)lup~iate dithiophosphoric acid product with a suitable nitrogen base
such as an amine. The amines used can be cyclic or acyclic, and typically they are
primary or secondary amines. The chief requirements are that the amine have sufficient
basicity to neutralize the dithiophosphoric acid being used, and that the resultant salt have
sufficient oil solubility to be useable-in the practice of this invention. The amine reactant
is employed in an arnount sufficient to neutralize the dithiophosphoric acid being used.
Usually, relatively mild reaction temperatures (e.g., room temperature up to about 100C)
are sufficient to cause the neutralization reaction between the amine and the
dithiophosphoric acid to take place at a suitable reaction rate. For further details, reference
may be had, for example, to U.S. Pat. No. 3,637,499.
~ase ~- / uuu
215~S27
.
Antioxidants
Preferably the compositions will contain a sufficient amount of one or more oil-soluble antioxidants in order to protect the composition from premature degradation in the
presence of air, especially at elevated temperatures. Typical antioxidants include secondary
5 aromatic amine antioxidants, hindered phenolic antioxidants, methylene-bridged phenolic
antioxidants, sulfurized phenolic antioxidants, sulfurized a-olefin antioxidants, copper-
cont~ining antioxidant compounds, phosphorus-containing antioxidants, and the like.
Preferably the antioxidant comprises at least one secondary aromatic amine
antioxidant. Most preferably the lubricant or additive concentrate additionally contains one
10 or more additional antioxidants such as (i) at least one oil-soluble sulfurized olefin having
about 10 to about 30 carbon atoms in the molecule (preferably an average of about 16 to
about 24 carbon atoms per molecule), and a sulfur content of about 15 to 25 wt%; andlor
(ii) at least one oil-soluble sulfurized phenol having about 25 to about 100 carbon atoms
in the molecule (preferably an average of about 50 to about 70 carbon atoms per
15 molecule), and a sulfur content of about 5 to 15 wt%; and/or (iii) an oil-soluble phenolic
antioxidant, preferably an oil-soluble hindered phenolic antioxidant; and/or (iv) an oil-
soluble copper-cont~ining antioxidant.
On an active ingredient basis, the antioxidants are typically used in the finished
lubricating oils in amounts within the range of about 0.01 to about 5 wt%, and more
20 preferably in the range of about 0.1 to about 2 wt%, based on the total weight of the
finished lubricant.
Demulsifiers
Demulsifier(s) which can be used, and preferably are used, in the compositions of
this invention can likewise be varied. These include oxyalkylated polyols, oxyalkylated
25 phenol-formaldehyde condensation products, oxyalkylated polyamines, alkyl benzene sulfo-
nates, polyethylene oxides, polypropylene oxides, block copolymers of ethylene oxide and
propylene oxide, amine glycol condensates, salts and esters of oil soluble acids, and the
like.
-18-
(~ase ~ 7()00
21~8G 27
Corrosion inhibitors
It is also preferred pursuant to this invention to employ in the lubricant
compositions and additive concentrates a suitable quantity of a corrosion or rust inhibitor.
This may be a single compound or a mixture of compounds having the property of inhibit-
5 ing corrosion or rusting of metallic surfaces. Materials of these types are known to thoseskilled in the art and a number of such materials are available as articles of commerce.
One very suitable commercially-available rust inhibitor is HiTEC~) 029 additive (Ethyl
Petroleum Additives, Inc.).
The lubricant compositions of this invention most preferably contain from 0.005
10 to 0.5% by weight, and especially from 0.01 to 0.2% by weight, of one or more corrosion
inhibitors.
Antifoam a~ents
Suitable antifoam agents include silicones and organic polymers such as acrylatepolymers. Various antifoam agents are described in Foam Control Agents by H. T. Kerner
15 (Noyes Data Corporation, 1976, pages 125-176). Mixtures of silicone-type antifoam agents
such as the liquid dialkyl silicone polymers with various other substances are also effec-
tive. Typical of such mixtures are silicones mixed with an acrylate polymer, silicones
mixed with one or more amines, and silicones mixed with one or more amine carboxylates.
The antifoam agent is employed in amount sufficient to inhibit foam formation in20 the finished lubricant. Such amount is usually quite small, e.g., in the range of from about
0.005 to about 0.5 wt%, although greater or lesser amounts can be used if and when the
circumstances warrant departures from this range.
Supplemental antiwear and/or extrerhe pressure additives
If desired, the compositions of this invention may contain one or more oil-soluble
25 supplemental antiwear and/or extreme pressure additives. These comprise a number of
well known classes of materials including, for example, sulfur-cont~ining additives, esters
of boron acids, esters of phosphorus acids, amine salts of phosphorus acids and acid esters,
higher carboxylic acids and derivatives thereof, chlorine-cont~ining additives, and the like.
On an active ingredient basis, supplemental antiwear and/or extreme pressure
-19-
Case EP-7000
21~8627
additives such as the foregoing, if used, are typically used in amounts such that the
finished lubricant contains in the range of 0.001 to 5 wt% of one or more such additives.
Supplemental ashless dispersants
If desired, the compositions of this invention can include one or more supplemental
ashless dispersants in order to supplement the dispersancy contributed by components a)
and b). The supplemental ashless dispersant(s) will of course differ from components a)
and b) in chemical composition. Examples include long chain hydrocarbyl polyamine
dispersants and Mannich polyamine dispersants. Such dispersants can be post-treated with
various post-treating agents in accordance with known technology. See, for example, a
representative listing of post-treating agents set forth in Table 4 of U.S. Pat. No. 5,137,980.
It ~,vill be appreciated that the term "ashless" as used herein does not mean that the
dispersant leaves no residues on engines parts with which the lubricant comes in contact.
Rather, it means that the dispersant does not itself contain metal. The dispersant may,
however, have a phosphorus or boron content, as these elements are not metals.
If used, the amount of such supplemental ashless dispersants will typically be such
that the finished lubricant will contain in the range of 0.01 to about 5 wt% of such
supplemental dispersants.
Pour point depressants
Another useful type of additive included in compositions of this invention is one
or more pour point depressants. Pour point depressants have the property of improving
the low temperature properties of oil-base compositions. Among the types of compounds
which function satisfactorily as pour point depressants in the compositions of this invention
are polymethacrylates, polyacrylates, condensation products of haloparaffin waxes and
aromatic compounds, and vinyl carboxylate polymers. Also useful as pour point
depressants are terpolymers made by polymerizing a dialkyl fumarate, vinyl ester of a fatty
acid and a vinyl alkyl ether. Generally, when they are present in the compositions of this
invention, the pour point depressants (on an active content basis) are present in amounts
~0 within the range of 0.01 to 5, and more often within the range of 0.01 to 1, weight percent
of the total composition.
-20-
Case EP-7000
, 21~62t7
Viscosity index improvers
Depending upon the viscosity grade required, the lubricant compositions can contain
up to 15 weight percent of one or more viscosity index improvers (excluding the weight
of solvent or carrier fluid with which viscosity index improvers are often associated as
S supplied). Among the numerous types of materials known for such use are hydrocarbon
polymers grafted with, for example, nitrogen-cont~ining polymers, olefin polymers such
as polybutene, ethylene-propylene copolymers, hydrogenated polymers and copolymers and
terpolymers of styrene with isoprene and/or butadiene, polymers of alkyl acrylates or alkyl
methacrylates, copolymers of alkyl methacrylates with N-vinyl pyrrolidone or
10 dimethylaminoalkyl methacrylate; post-grafted polymers of ethylene-propylene with an
active monomer such as maleic anhydride which may be further reacted with an alcohol
or an alkylene polyamine; styrene/maleic anhydride polymers post-treated with alcohols
and/or ~mines, and the like.
Dispersant viscosity index improvers which additionally possess antioxidant properties
15 are also known and reported in the patent literature, and can be employed in the
compositions of this invention.
Friction reducers
These materials, sometimes Icnown as fuel economy additives, include such
substances as the alkyl phosphonates as disclosed in U.S. Pat. No. 4,356,097, aliphatic
20 hydrocarbyl-substituted succinimides derived from ammonia or alkyl monoamines as
disclosed in European Patent Publication No. 20037, dimer acid esters as disclosed in U.S.
Pat. No. 4,105,571, oleamide, and partial fatty acid esters of polyhydroxy compounds such
as glycerol monooleate and pentaerythritol monooleate. Such additives, when used are
generally present in amounts within~ in the range of 0.1 to 5 weight percent. Glycerol
25 oleates are usually present in amounts in the range of about 0.05 to about 1.0 weight
percent based on the weight of the formulated oil.
Other suitable friction reducers include aliphatic amines or ethoxylated aliphatic
amines, aliphatic fatty acid amides, aliphatic carboxylic acids, aliphatic carboxylic esters,
aliphatic carboxylic ester-amides, aliphatic phosphates, aliphatic thiophosphonates, aliphatic
30 thiophosphates, etc., wherein the aliphatic group usually contains above about eight carbon
-21-
Case EP-7000
2158S27
atoms so as to render the compound suitably oil soluble.
Proportions
It will be understood from the foregoing that whatever components are selected for
use in the compositions of this invention, each component will be present in an amount
5 at least sufficient for it to exert its intended function or functions in the finished lubricant
composition.
Base Oils
The lubricant compositions of this invention may be formed from natural (e.g.,
mineral or vegetable oils) or synthetic base oils, or blends thereof.
Suitable mineral oils include those of applop,iate viscosity refined from crude oil
of any source including Gulf Coast, Midcontinent, Pennsylvania, California, Alaska,
Middle East, North Sea and the like. Standard refinery operations may be used in process-
ing the mineral oil. Among the general types of petroleum oils useful in the compositions
of this invention are solvent neutrals, bright stocks, cylinder stocks, residual oils, hydro-
cracked base stocks, paraffin oils including pale oils, and solvent extracted naphthenic oils.
Such oils and blends of them are produced by a number of conventional techniques which
are widely known by those skilled in the art.
Among the suitable synthetic oils are homo- and interpolymers of C,-CI2 olefins,carboxylic acid esters of both monoalcohols and polyols, polyethers, silicones, polyglycols,
silicates, alkylated aromatics, carbonates, thiocarbonates, orthoformates, phosphates and
phosphites, borates and halogenated hydrocarbons. Representative of such oils are homo-
and interpolymers of C2-C,2 monoolefinic hydrocarbons, alkylated benzenes (e.g., dodecyl
ben~enes, didodecyl benzenes, tetradecyl benzenes, dinonyl benzenes, di-(2-ethylhexyl)ben-
zenes, wax-alkylated naphthalenes); and polyphenyls (e.g., biphenyls, terphenyls).
Alkylene oxide polymers and interpolymers and derivatives thereof where the
terminal hydroxyl groups have been modified by esterification, etherification, etc.,
constitute another class of synthetic oils. These are exemplified by the oils prepared
through polymerization of alkylene oxides such as ethylene oxide or propylene oxide, and
the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl polyisopropylene
Case EP-7000
21~62~
-
glycol ether having an average molecular weight of 1,000, diphenyl ether of polyethylene
glycol having a molecular weight of 500-1,000, diethyl ether of polypropylene glycol
- having a molecular weight of 1,000-1,500) or mono- and poly-carboxylic esters thereof,
for example, the acetic acid ester, mixed C3-C6 fatty acid esters, or the C13 Oxo acid diester
5 of tetraethylene glycol.
Another suitable class of synthetic oils comprises the esters of dicarboxylic acids
(e.g., phthalic acid, succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fu-
maric acid, adipic acid, linoleic acid dimer) with a variety of alcohols ~e.g., butyl alcohol,
hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol). Specific examples
10 of these esters include dibutyl adipate, di(2-ethylhexyl) adipate, didodecyI adipate, di-
(tridecyl) adipate, di(2-ethylhexyl~ sebacate, dilauryl sebacate, di-n-hexyl filrnarate, dioctyl
sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phth~l~te, didecyl phth~l~te,
di(eicosyl) sebacate, the 2-ethylhexyl diester of linoleic acid dimer, and the complex ester
formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and
15 two moles of 2-ethylhexanoic acid.
Other esters which may be used include those made from C3-CI8 monocarboxylic
acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, penta-
erythritol and dipentaerythritol. Trimethylol propane tripelargonate, pentaerythritol tetra-
caproate, the ester forrned from trimethylolpropane, caprylic acid and sebacic acid, and the
20 polyesters derived from a C4-C14 dicarboxylic acid and one or more aliphatic dihydric C3-
C,~ alcohols such as derived from azelaic acid or sebacic acid and 2,2,4-trimethyl-1,6-
hexanediol serve as examples.
Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-
siloxane oils and silicate oils comprise another class of synthetic lubricants (e.g., tetraethyl
25 silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl) silicate, tetra-(p-tert-butylphenyl)
silicate, poly(methyl)siloxanes, and poly(methylphenyl)siloxanes. Other synthetic
lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phos-
phate, trioctyl phosphate, triphenyl phosphite, and diethyl ester of decane phosphonic acid.
Also useful as base oils or as components of base oils are hydrogenated or
30 unhydrogenated liquid oligomers of C6-CI6 a-olefins, such as hydrogenated or
unhydrogenated oligomers formed from 1-decene. Methods for the production of such
-23 -
Case EP-7000
21S~27
-
liquid oligomeric l-alkene hydrocarbons are known and reported in the literature.
Additionally, hydrogenated l-alkene oligomers of this type are available as articles of
commerce. Blends of such materials can also be used in order to adjust the viscometrics
of the given base oil. As is well known, hydrogenated oligomers of this type contain little,
5 if any, residual ethylenic unsaturation. Preferred oligomers are forrned by use of a Friedel-
Crafts catalyst (especially boron trifluoride promoted with water or a C,20 alkanol)
followed by catalytic hydrogenation of the oligomer so formed using procedures such as
are described in the foregoing U.S. patents.
Other catalyst systems which can be used to form oligomers of l-alkene
10 hydrocarbons, which, on hydrogenation, provide suitable oleaginous liquids include Ziegler
catalysts such as ethyl aluminum sesquichloride with titanium tetrachloride, aluminum
alkyl catalysts, chromium oxide catalysts on silica or alumina supports and a system in
which a boron trifluoride catalyst oligomerization is followed by treatment with an organic
peroxlde.
Likewise, various proprietary synthetic lubricants such as KETJENLUBE synthetic
oil of Akzo Chemicals can be employed either as the sole base lubricant or as a component
of the base lubricating oil.
Typical vegetable oils that may be used as base oils or as components of the base
oils include castor oil, olive oil, peanut oil, rapeseed oil, corn oil, sesame oil, cottonseed
20 oil, soybean oil, sunflower oil, safflower oil, hemp oil, linseed oil, tung oil, oiticica oil,
jojoba oil, meadowfoam oil, and the like. Such oils may be partially or fully
hydrogenated, if desired.
The fact that the base oils used in the compositions of this invention may be
composed of (i) one or more mineral oils, (ii) one or more synthetic oils, (iii) one or more
25 vegetable oils, or (iv) a blend of (i) and (ii), or (i) and (iii), or (ii) and (iii), or ~i), (ii) and
(iii) does not mean that these various types of oils are necessarily equivalents of each
other. Certain types of base oils may be used in certain compositions for the specific
properties they possess such as biodegradability, high temperature stability, non-
flammability or lack of corrosivity towards specific metals (e.g. silver or cadmium). In
30 other compositions, other types of base oils may be plefell~d for reasons of availability
or low cost. Thus, the skilled artisan will recognize that while the various types of base
-24-
Case EP-7000 21~ 8 6 2 7
-
oils discussed above may be used in the compositions of this invention, they are not
necessarily functional equivalents of each other in every instance.
In the illustrative examples of finished lubricants of this invention set forth in Table
I, component a) is HiTEC(~ 646 additive (Ethyl Petroleum Additives, Inc.~, and component
5 b) is HiTECg) 7714 additive (Ethyl Petroleum Additives, Inc.). These di~ aLll~ meet
all of the respective parameters given above for components a) and b). Component a) is
a 60% mineral oil solution of active ingredients and component b) is a 40% mineral oil
solution of active ingredients. Components c-l) and c-2) are HiTEC(~) 7304 and 614 addi-
tives, respectively. These are low-base calcium alkylbenzene sulfonates, each having a
10 nominal TBN below about 50. The term "Acrylic PPD" refers to a polymeric acrylic pour
point depressant. The lubricants of Exarnples 1-4 and 6-20 are SAE 15W-40 lubricants,
the lubricant of Example 5 is of grade SAE 30, and the lubricant of Example 21 is of
grade SAE lOW-30.
Case EP-7000
215~627
Table I - Illustrative Compositions
Components Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5
Component a) 4 3.3 3.5 3.3 3.5
Component b) 3.5 3.5 3.5 3.5 3.s
S OLOA-219 additive -- 1.1 0.87 1.1 0.38
HiTEC 7334 additive 1 -- -- -- --
HiTEC 7465 additive -- -- -- -- 0.7
HiTEC 7304 additive 1.25 -- -- -- --
HiTEC 614 additive -- 0.7 0.7 0.7 0.7
HiTEC 611 additive 0.45 0.54 0.41 0.54 0.45
HiTEC 7169 additive 1.02 0.8 0.8 0.8 0.8
HiTEC 7198 additive 0.31 0.5 0.5 0.5 0.5
HiTEC 7637 additive 0.4 0.3 0.4 0.3 0.45
Naugalube 438L additive -- 0.2 0.2 0.2 0.2
ECA 8743 additive 0.5 0.7 0.6 0.7 --
HiTEC 619 additive -- -- -- -- 0.33
HiTEC 7084 additive -- 0.4 -- 0.4 --
HiTEC 4760 additive t.2 -- -- -- --
HiTEC 4733 additive -- -- -- -- 0.5
Tolad 326 additive 0.01 0.01 0.005 0.01 ~ 0.005
HiTEC 029 additive -- -- -- -- 0.15
Foam inhibitor 0.03 . 0.03 0.03 0.03 0.03
Diluent oil 0.33 0.42 0.685 0.42 0.805
VI improver 6.8a 7.6b 7.82C 8.20C
Acrylic PPD -- -- 0.15 0.15 --
HiTEC 672 additive 0.2 -- -- -- 0.2
100N base oil -- -- -- 15.04 --
150N base oil 67.15 58.33 56.68 -- --
-26-
Case EP-7000
21S8627
240N base oil -- -- -- 64.11 --
370N base oil -- -- -- -- 86 80
600N base oil 11.85 21.57 23.15 -- --
a) Star polymer viscosity index improver
5 b) Non-dispersant olefin copolymer viscosity index improver
c) Dispersant olefin copolymer viscosity index improver
Case EP-7000
21S8627
Table I (continued) - Illustrative Compositions
Components Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex 10
Component a) 3.5 3.5 3.5 3.5 5.0
Component b) 3.5 3.5 3.5 3.5 3.0
S OLOA-219 additive -- -- 0.38 0.38 1.7
HiTEC 7465 additive 1.37 1.37 0.75 0.7 --
HiTEC 6I4 additive 0.7 0.7 0.7 0.7 1.0
HiTEC 611 additive 0.39 0.39 0.5 0.45 0.15
HiTEC 7169 additive 0.8 0.8 0.8 0.8 --
HiTEC 7198 additive 0.5 0.5 0.5 0.5 0.9
HiTEC 7637 additive -- -- 0.4 0.45 --
Witco M-400 T/G additive 0.45 0.45 -- -- --
Naugalube 438L additive 0.2 0.2 0.2 0.2 0.4
ECA 8743 additive 0.5 -- 0.5 -- 0.7
HiTEC 619 additive -- 0.33 -- 0.33 --
HiTEC 4760 additive 0.5 0.5 -- -- --
HiTEC 4733 additive -- -- 0.5 0.5 --
Tolad 326 additive 0.005 0.005 0.005 0.005 --
HiTEC 029 additive 0.12 0.12 0.15 0.15 --
Foam inhibitor 0.03 0.03 0.03 0.03 0.03
Diluent oil 0.435 0.605 0.585 0.805 0.52
VI improver 7.75C 7.75C 7.75C 8.0b 11 od
Acrylic PPD 0.15 0.15 0.15 --
HiTEC 672 additive -- -- -- 0.3 0.2
150N base oil 56.17 56.17 56.17 -- --
170N base oil -- -- -- 60.6 64.0
370N base oil -- -- -- 18.1 11.4
600N base oil 22.93 22.93 22.93 -- --
~) Non-dispersant olefin copolymer viscosity index improver
30 c) Dispersant olefin copolymer viscosity index improver
d)Dispersant olefin copolymer viscosity index improver
-28-
Case EP-7000
21S8627
Table I (continued) - Illustrative Compositions
Components Ex 11 Ex 12 Ex 13 Ex I4 Ex 15
Component a) 5.0 5.0 5.0 5.0 3.5
Component b) 3.0 3.0 3.0 3.0 3.5
OLOA-219 additive 1.75 -- 1.75 -- --
HiTEC 7465 additive -- 2.4 -- 2.4 1.37
HiTEC 614 additive 1.0 1.0 1.0 1.0 0.7
HiTEC 611 additive -- -- -- -- 0.41
HiTEC 7169 additive 0.3 0.3 0.3 0.3 0.8
HiTEC 7198 additive 0.65 0.65 0.65 0.65 0.5
HiTEC 7637 additive -- -- -- -- 0.4
Naugalube 438L additive 0.4 0.4 0.4 0.4 0.2
ECA 8743 additive 0.7 -- -- -- 0.6
HiTEC 4760 additive -- -- 1.0 1.0 --
HiTEC 4733 additive -- 0.5 -- --
Tolad 326 additive -- -- -- -- 0.005
Foam inhibitor 0.03 0.04 0.04 0.04 0.03
Diluent oil 0.52 0.51 0.51 0.51 0.485
VI improver 10.5d 10.0d lo.Sd 10 od 7 79c
Acrylic PPD -- -- -- -- 0.15
HiTEC 672 additive 0.2 0.2 0.2 0.2 --
150N base oil -- -- -- -- 56.49
170N base oil 66.95 67.00 66.65 66.50 --
370N base oil 9.00 9.00 9.00 9.00 --
600N base oil -- -- -- -- 23.07
c) Dispersant olefin copolymer viscosity index improver
d) Dispersant olefin copolymer viscosity index improver
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- 21~27
Table I (continued) - Illustrative Compositions
Components Ex 16 Ex 17 Ex 18
Component a) 3.5 3 5 3 5
Component b) 3.5 3.5 3.5
OLOA-219 additive -- 0.46 0.46
HiTEC 7465 additive -- 0.67 0.67
HiTEC 614 additive 1.25 1.25 0.7
HiTEC 611 additive 1.48 0.7 0.39
HiTEC 7169 additive 0.8 0.8 0.8
HiTEC 7198 additive 0.5 0.5 0.5
HiTEC 7636 additive -- 0.1 --
Witco M-400 T/G additive -- -- 0.45
Naugalube 438L additive 0.05 0.1 0.2
ECA 8743 additive -- -- 0.5
HiTEC 4760 additive 1.0 -- --
HiTEC 4733 additive -- 0.5 --
Tolad 326 additive -- -- 0.005
HiTEC 029 additive -- 0.2 --
HiTEC 093 additive 0.3 0.3 --
Foam inhibitor 0.014 0.03 0.03
Diluent oil- 0.906 0.59 0.795
VI improver 5.4d 5.41 d 6.5d
160N base oil 77.24 77.32 81.00
650N base oil 4.06 4.07 --
25 d) Dispersant acrylic viscosity index improver
e) Dispersant olefin copolymer viscosity index improver
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21~8627
Table I (continued) - Illustrative Compositions
Components Ex 19 Ex 20 Ex 21
Component a) 5.0 5.0 3.5
Component b) 3.0 3.0 3.5
OLOA-219 additive -- 0.7 0.38
HiTEC 7465 additive 2.4 1.4 0.7
HiTEC 614 additive 1.0 1.0 0.7
HiTEC 611 additive -- -- 0.45
HiTEC 7169 additive 0.3 0.3 0.8
HiTEC 7198 additive 0.65 0.65 0.5
HiTEC 7637 additive -- -- 0.45
Naugalube 438L additive 0.4 0.4 0.2
HiTEC 4760 additive -- 0.6 --
HiTEC 4733 additive 0.6 -- 0.5
Tolad 326 additive -- -- 0.005
HiTEC 029 additive -- -- 0.15
Foam inhibitor 0.04 0.04 0.03
Diluent oil 0.51 0.52 0.805
VI improver 10.0e 10 oe 7 of
HiTEC 672 additive 0.2 0.2 0.3
l00N base oil -- -- 29.5
170N base oil 66.9 65.5 50.2
370N base oil 9.0 10.3 --
e) Dispersant olefin copolymer viscosity index improver
25 f) Non-dispersant olefin copolymer viscosity index improver
Case EP-7000
- 21~8~27
The compositions of this invention exhibit a reduced tendency to deteriorate under
conditions of use and thereby reduce wear and the formation of such undesirable deposits
as varnish, sludge, carbonaceous materials and resinous materials which tend to adhere to
various engine parts and reduce the efficiency of the engines.
The performance of the lubricants of this invention are evaluated by subjecting
lubricant compositions to a number of engine oil tests which have been designed to
evaluate a variety of performance characteristics of engine oils. For a lubricant to be
qualified for particular industry service classifications, the lubricant must pass certain
specified engine oil tests. However, lubricants which pass one or more of the individual
10 tests are also useful for particular applications.
- The ASTM Sequence, IIIE engine oil test has been recently established as a means
of defining the high-temperature wear, oil thickening, and deposit protection capabilities
of SG engine oils. The IIIE test, which replaces the Sequence IIID test, provides improved
discrimination with respect to high temperature c~m~h~ft and lifter wear protection and oil
15 thickening control. The IIIE test utilizes a Buick 3.8L V-6 model engine which is operated
on leaded fuel at 67.8 bhp and 3000 rpm for a maximurn test length of 64 hours. A valve
springload of 230 pounds is used. A 100% glycol coolant is used because of the high
engine operating-temperatures. Coolant outlet temperature is m~int~ined at 11 8C, and the
oil temperature is m~int~ined at 149C at an oil pressure of 30 psi. The air-to-fuel ratio
20 is 16.5, and the blow-by rate is 1.6 cfm. The initial oil charge is 146 ounces.
The test is termin~ted when the oil level reaches 28 ounces low at any of the 8-hour check intervals. When the tests are concluded before 64 hours because of low oil
level, the low oil level has generally resulted from hang-up of the heavily oxidized oil
throughout the engine and its inability to drain to the oil pan at the 49C oil check
25 temperature. Viscosities are obtained on the 8-hour oil samples, and from this data, curves
are plotted of percent viscosity increase versus engine hours. A maximum 375% viscosity
increase measured at 40C at 64 hours is required for APE classification SG. The engine
sludge requirement is a minirnum rating of 9.2, the piston varnish a minimurn of 8.9, and
the ring land deposit a minimum of 3.5 based on the CRC merit rating system. Details
30 of the Sequence IIIE Test are contained in the ASTM Research Report: D-2: 1225 of April
1, 1988 including any and all arnendments detailed by the Information Letter System (up
Case EP-7000
21~8~27
to November 1, 1990).
The results of Sequence IIIE tests conducted on lubricants of Examples 2, 6, 7, 8,
14 and 17 are surnmarized in Table II wherein the following abbreviations are used:
Adj Hrs Adjusted hours to reach 375% viscosity increase in the oil. Test specification is 64 hours minimum.
Eng Sludge Average engine sludge rating. Test specification is a rating of 9.2
minimum.
Avg Varnish Average engine varnish rating. Test specification is a rating of 8.9
mmlmum.
Avg RLD Average adjusted oil ring land deposit rating. Test specification is
a rating of 3.5 minimum.
Avg Cam Wear Average cam wear in microns. Test specification is 30 microns
maxlmum.
Max Cam Wear Maximum cam wear in microns. Test specification is 64 microns
maximum.
# Stuck Rings Test Specification is a maximum of one stuck ring with an average
adjusted oil ring land deposit rating over 3.5.
Table II - Secuence IIIE Tests
Results Ex. 2 Ex. 6 Ex. 7 Ex. 8 Ex. 14 Ex. 17
Adj Hrs 71.3 76.9 78.1 72.4 82.6 72.6
Eng Sludge 9.49 9.48 9.50 9.54 9.54 9.57
Avg Varnish 9.22 9.04 8.95 9.06 9.05 9.27
Avg RlD 6.57 8.26 7.53 7.90 7.36 5.53
Avg Can Wear 5.2 9.2 4.3 1.5 7.1 6.2
Max Cam Wear 8 14 7 6 13 13
# Stuck Rings 0 0 0 0 0 - 0
End Result Pass Pass Pass Pass Pass Pass
Case EP-7000
21~627
-
The CRC L-38 test is a test developed by the Coor-lin~ting Research Council. This
test method is used for determining the follo~,ving characteristics of crankcase lubricating
oils under high temperature operating conditions antioxidation, corrosive tendency, sludge
and varnish producing tendency, and viscosity stability. The CLR engine features a fixed
5 design, and is a single cylinder, li~uid cooled, spark-ignition engine operating at a fixed
speed and fuel flow. The engine has a one-quart crankcase capacity. The procedure
requires that the CLR single cylinder engine be operated at 3150 rpm, approximately 5
bhp, 290F oil gallery temperature and 200F coolant-out temperature for 40 hours. The
test is stopped every 10 hours for oil sampling and topping up. The viscosities of these
10 oil samples are deterrnined, and these numbers are reported as part of the te st result.
A special copper-lead test bearing is weighed before and after the test to deterrnine
the weight loss due to corrosion. After the test, the engine also is rated for sludge and
varnish deposits, the most important of which is the piston skirt varnish. The primary
performance criteria for API Service Classification SG are bearing weight loss, mg, max
15 of 40 and a piston skirt varnish rating (minimum) of 9.0
The L-38 procedure is set forth in ASTM D-5119, including any and all
amendments detailed by the Information Letter System (up to November 1, 1990).
Table III summarizes the L-38 test results on four lubricants of this invention. In
Table III, the lowest viscosity measurements are expressed in terrns of centistokes (cSt)
20 at 100C.
Table III - L-38 Tests
Results Ex. 6 Ex. 7 Ex. 9 Ex. 14
Bearing Weight Loss, mg 18.8 14.9 18.4 28.7
PSV Rating 9.7 9.6 9.6 9.6
Lowest Vis Measurement 14.05 13.89 13.09 13.80
End Result Pass Pass Pass Pass
The Caterpillar IK test procedure has been correlated with direct injection engines
used in heavy-duty service, particularly in respect of piston and ring groove deposits. The
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2i5~6~7
-
test procedure is described in ASTM Research Report RR:DO2-1273, "Caterpillar lK Test
ASTM Research Report."
Results on different compositions of this invention when subjected to the lK test
procedure are summarized in Table IV.
Table IV - lK Tests
Results Ex. 1 Ex. 2 Ex. 11 Ex. 14
Top Groove Fill, % max. 12 11 7 22
Weighted Total Demerits 258.3 228.9 210.5 317
Top Land Heavy Carbon, % 0 0 0
Oil Consumption, glKw-hr 0.19 0.16 0.13 0.18
End Result Pass Pass Pass Pass
The Caterpillar lN diesel engine test is a recent test procedure used for predicting
piston deposit formation in 4 stroke cycle, direct injection, diesel engines which have been
calibrated to meet 1994 U.S. Federal Exhaust Emissions requirements for heavy-duty
l5 engines operated on fuel cont~ining less than 0.05 weight percent sulfur. The primary test
limit requirements on deposit control are: top groove fill, 15.7% max; weighted total
demer,ts, 286; and top land heavy carbon, 3%.
Results on four lubricants of this invention using the Caterpillar lN test procedure
are summarized in Table V.
Table V - lN Tests
Results Ex. 12 Ex. 13 Ex. 15 Ex. 16
Top Groove Fill, % max. 10 9 8 10
Weighted Total Demerits 272.7 275 190.6 239.8
Top Land Heavy Carbon, % 0 0 0 0
Oil Consumption, g/Kw-hr 0.15 0.25 0.12 0.34
End Result Pass Pass Pass Pass
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2158627
The Mack T-6 test procedure is another qualification test for heavy duty engine
oils. The test has been correlated with vehicles equipped with engines used in high-speed
operation, particularly with respect to deposits, oil consumption, and piston ring wear. The
test procedure itself is described in ASTM Research Report RR:DO2:1219, Multicylinder
5 Engine Test Procedure for the Evaluation of Lubricants - Mack T-6.
Results from T-6 tests on several engine oils of this invention are summarized in
Table VI.
Table VI - T-6 Tests
Results Ex. 2 Ex. 8 Ex. 19
Avg Oil Consumption, Merits 37 37.4 25.4
Avg Ring Weight Loss, Merits 40 40 40
Max Piston Proudness, Merits 22.9 27.1 28.6
Viscosity Increase, Merits 22.5 17.6 22.4
Piston Deposits, Merits 17.2 15.6 19.2
Total Mack Merits 139.5 137.8 135.6
End Result Pass Pass Pass
The Mack T-8 test is a relatively new engine test procedure. It involves
determining viscosity increase due to soot formation during engine operation over a period
of 250 hours. In order to pass the test, the 100C kinematic viscosity increase of the
20 engine oil at a 3.8% soot level must not exceed 11.5 cSt. When the lubricants of
Examples lD and 20 were subjected to this procedure the results were viscosity increases
of only 3.98 and 3.08 cSt, respectively, at the 3.8% soot level.
Another common qualification test is the Sequence IID test procedure. This test
measures the rusting and corrosion characteristics of motor oils. The test procedure is set
25 forth in ASTM STP 315H Part 1, including any and all amendments detailed by the
Information Letter System (up to November 1, 1990). The test relates to short trip service
under winter driving conditions as encountered in the United States. The sequence IID
uses an Oldsmobile 5.7 liter (350 CID) V-8 engine run under low speed (1500 rpm), low
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~ase ~ /uw
21~862'7
load conditions ~25 bhp) for 28-hours with engine coolant-in at 41C and the coolant-out
at 43C. Following this, the test operates for two hours at 1500 rpm with coolant-in at
47C and coolant-out at 49C. After a carburetor and spark plug change, the engine is
operated for the final two hours under high speed (3600 rpm), moderate load conditions
5 (100 bhp) with coolant-in at 88C and the coolant-out at 93C. Upon completion ofthe
test (32 hours), the engine is inspected for rust using CRC rating techniques.
The results obtained on subjecting several engine oils of this invention to the IID
procedure are sumrnarized in Table VII.
Table VII - Sequence III~ Tests
Results Ex. 9 Ex. 17 Ex. 18
Average Rust 8.67 8.53 8.46
Average Crankcase Pressure 0.07 0.03 0.04
Maximurn Crankcase Pressure 0.60 0.04 0.06
End Result Pass Pass Pass
The Sequence VE test procedure is described in ASTM Sequence VE Test
Procedure, Seventh Draft, May 19, 1988, including and all amendrnents detailed by the
Information Letter System (up to November 1, 1990).
The test uses a 2.3 liter 4-cylinder overhead cam engine equipped with a multi-
point electronic fuel injection system, and the compression ratio is 9.5:1. The test
20 procedure uses the same format as the Sequence VD test with a four-hour cycle consisting
of three different stages. The oil temperatures (F) in Stages I, II, and III are 155/210/115,
and the water temperatures (F) in three stages are 125/185/115, respectively. The test oil
charge volume is 106 oz., and the rocker cover is jacketed for control of upper engine
temperature. The speeds and loads of the three stages have not been changed from the VD
25 test. The blow-by rate in Stage I is increased to 2.00 CFM from 1.8 CFM, and the test
length is 12 days. The PCV valves are replaced every 48 hours in this test.
At the end of the test, engine sludge, rocker cover sludge, piston varnish, average
varnish and valve train wear are rated.
-37-
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21586~7
Table VIII summarizes the Sequence VE test results on the lubricants of Examples4 and 21.
Table VIII - Sequence VE Tests
Results Ex. 3 Ex. 21 Test Limits
Average Sludge 9.38 9.49 9.0 min.
Rocker Arm Cover Sludge 9.2 9.27 7.0 min.
Average Engine Varnish 6.18 6.20 5.0 min.
Piston Skirt Varnish 6.79 7.53 6.5 min.
Average Cam Wear, mils 0.58 0.37 5.0 max.
Maximum Cam Wear, mils 0.5 0.10 15.0 max.
End Result Pass Pass
`A test used for measuring corrosion is the Cl-mmin~ L-10 Bench Corrosion Test
which forms part of tne new category, PC-6, to ASTM D4485, Standard Specification for
Performance of Engine Oils. This test has been shown to predict corrosion of engine oil
lubricated copper, lead, or tin cont~ining components used in diesel engines. To pass this
test, the maximum increase of metals in terms of parts per million (ppm) in the oil are as
follows: copper, 20 ppm; lead, 60 ppm; tin, 50 ppm. In addition, the maximum copper
corrosion rating pursuant to ASTM D130 is 3a. The procedure is described in ASTMResearch Report RR:D02:DDDD Cumminc Bench Corrosion Test.
L-10 corrosion results on several compositions of this invention are summarized
in Table IX, wherein "nc" means no change in color of test specimen from its original
color.
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213~627
Table IX - L-10 Corrosion Tests
Results EY. 2 Ex. 4 Ex. 14
Copper Rating la la la
Copper in oil, ppm 8 18 8
Lead in oil, ppm 17, nc 47 nc 24
Tin in oil, ppm 0 nc 0 nc 0
End Result Pass Pass Pass
The General Motors 6.2 Liter test is another test used for measuring engine wear,
and in particular rolling contact wear. This is a diesel engine test which has been shown
10 to correlate with hydraulic roller cam follower pin wear in medium-duty indirect injection
diesel engines used in broadly based field operations. Details of the test procedure are set
forth in ASTM Research Report RR:D02:CCCC Development of the GM 6.2 Liter Wear
Test.
Table X summarizes the results obtained when the compositions of Examples 2, 9
15 and 14 were subjected to the GM 6.2 liter wear test.
Table X - General Motors 6.2 Liter Wear Tests
Results Ex. 2 Ex. 9 Ex. 14
Minimum Wear, mils 0.16 0.08 0.12
Maximum Wear, mils 0.40 0.36 0.26
Average Wear, mils 0.30 0.26 0.18
End Result Pass Pass Pass
As pointed out above, the dispersant compositions of this invention are more
effective in providing high temperature piston cleanliness performance than the closest
known prior art dispersant composition, a dispersant composition which was used in heavy
25 duty diesel lubricants. That composition was composed of component b) as described
above and a succinimide dispersant of the same type as the above component a) except
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~_d~C: ~r- / vuu
215~627
that the mole ratio of (i) to (ii) thereof was 2:1 instead of below about 1.85 as required
pursuant to this invention. For evaluation of high temperature piston cleanliness
perforrnance, the standard Caterpillar lK procedure was used. When employed as the
dispersant on three occasions in an SAE 15W-40 heavy duty engine oil formulation that
5 satisfied the requirements of API classification CE, the prior art dispersant gave three
failing results in the Caterpillar lK engine test procedure. In sharp contrast and as shown
in Table IV, four different SAE 15W-40 heavy duty engine oils of this invention in which
the dispersant was a dispersant composition of this invention all passed the Caterpillar 1 K
engine test. All such test data are surnrnarized for ready reference in Table XI, wherein0 the following abbreviations are used:
TGF is Top Groove Fill, % max.;
WTD is Weighted Total Demerits;
TLHC is Top Land Heavy Carbon, %; and
OC is Oil Consurnption, g/Kw-hr.
Table XI - lK Tests
Prior Art Dispersant Dis~lsant of the Invention
Results No. 1 No. 2 No. 3 Ex 1 Ex 2 Ex 11 Ex 14
TGF 70 38 21 12 11 7 22
WTD 441.1 282.3 400.8 258.3 228.9 210.5 317
TLHC 8 1 45 0 0 0
OC 0.19 0.20 1.05 0.19 0.16 0.13 0.18
End Fail Fail Fail Pass Pass Pass Pass
Result
As used herein the term "oil-soluble" means that the substance under discussion
should be sufficiently soluble at 20C in the base oil selected for use to reach at least the
25 minimum concentration required to enable the substance to serve its intended function.
Preferably the substance will have a substantially greater solubility in the base oil than this.
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215~627
However, the substance need not dissolve in the base oil in all proportions.
Each and every U.S. patent docurnent referred to hereinabove is fully incorporated
herein by reference.
-41 -
